1. Technical Field
The present invention relates to applying adhesive to books which are conveyed along a predetermined path such as in a bindery line, and is particularly directed to an apparatus and method for applying a length of adhesive to a first book and another length of adhesive to a second book spaced a predetermined distance apart from the first book as the books are being conveyed.
2. Background Art
Glue applying systems for applying adhesive to books are well known in the art. Typically, such a glue applying system includes a roller which is rotatable about its longitudinal central axis and which has a portion of its periphery located in a glue supply containing a supply of adhesive. As the roller rotates, its outer surface picks up adhesive. The books are moved into contact with the adhesive on the outer surface of the rotating roller. When the books come in contact with the adhesive, the adhesive is transferred from the outer surface of the rotating roller to the moving books.
A problem associated with the glue applying system just described is that some adhesive on the outer surface of the rotating roller may not transfer to the books. The adhesive that does not transfer to the books may result in a buildup of excessive adhesive on the outer surface of the rotating roller. A buildup of excess adhesive on the outer surface of the rotating roller is undesirable because this affects the proper transfer of adhesive from the rotating roller to the books and results in increased adhesive consumption than otherwise would be if there was no buildup of excess adhesive.
A known way to minimize the buildup of excess adhesive on the outer surface of the rotating roller is to use one or more scrapers located around the outer periphery of the rotating roller. Through the operation of an arrangement of mechanical cams, the scraper is moved into and out of contact with the outer surface of the rotating roller to remove the excess adhesive on the rotating roller. A disadvantage in using the scrapers is that the combination of the mechanical cams and the scrapers is relatively large in size. The result is a relatively large glue applying system which occupies a relatively large amount of space.